16593 02 tủ tài liệu bách khoa
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16593 02 tủ tài liệu bách khoa
CHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoanagerOffice of Ground H ater and Drinking Hater U.S. Environmental Protection AgencySeattle, ỈỈA•r ••Senior Micro biologistOffice of Ground H ater and Drinking H arer U.S. Environmental Protection Agency Washington. D. c.Health and aesthetics arc the principal motivations for water treatment. In the 16593 02 tủ tài liệu bách khoa late 1800s and early 1900s, acute waterborne diseases, such as cholera and typhoid lever, spurred development and proliferation of filtration and chl16593 02 tủ tài liệu bách khoa
orination plants. Subsequent identification in water supplies of additional disease agents (such as Legionella. Cryptosporidium, and Giardia) and contCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoaes such as granular activated carbon (GAC) adsorption and ion exchange were occasionally applied to water treatment to control taste- and odor-causing compounds and to remove contaminants such as nitrates. In addition, water treatment can be used to protect and preserve the distribution system.A var 16593 02 tủ tài liệu bách khoaiety of developments in the water quality field since the 1970s and an increasing understanding of health effects have created an upheaval in the wate16593 02 tủ tài liệu bách khoa
r treatment field. With the identification in waler of low levels of potentially harmful2.2CHAPTER TWOorganic compounds, a coliform-free and low-turbiCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoauality within distribution systems. Increasing pressures on watersheds have resulted in a heavier incoming load of microorganisms to many treatment plants. Although a similarly intense reevaluation of the aesthetic aspects of water quality has not occurred, aesthetic quality is important. Problems, 16593 02 tủ tài liệu bách khoasuch as excessive minerals, fixture staining, and color, do affect consumer acceptance of the water supply. However, significant advances in the ident16593 02 tủ tài liệu bách khoa
ification of taste- and odorcausing organisms and their metabolites have occurred within the last two decades.This chapter summarizes the current statCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoats of toxicology, separate sections of the chapter are devoted to pathogenic organisms, indicator organisms, inorganic constituents, organic compounds, disinfectants and disinfection by-products, and radionuclides. Emphasis is placed on contaminants that occur more frequently and al levels that are 16593 02 tủ tài liệu bách khoaof concern for human health. Because of major interest and pending changes regarding disinfection by-products as of this writing, more detail has been16593 02 tủ tài liệu bách khoa
included for that section. Taste and odor, turbidity, color, mineralization, and hardness are discussed in a final section devoted to aesthetic qualiCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoas and occurrence information. The cited references and additional sources must be studied carefully and public health officials consulted prior to making any decisions regarding specific contamination problems. Due to space considerations, citations have been limited to those most generally applicab 16593 02 tủ tài liệu bách khoale, especially those from U.S. governmental organizations,such as the U.S. Environmental Protection Agency (USEPA) and the Centers for Disease Control16593 02 tủ tài liệu bách khoa
and Prevention (CDC). Various stale governments in the United States have more stringent standards based on different interpretations of studies or dCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoaile series on individual chemicals produced by the Agency for Toxic Substances and Disease Registry (ATSDR), and the Integrated Risk Information System (IRIS) database of the USEPA. I For chemicals, emphasis has been given to possible health effects from long-term exposure rather than to the effects 16593 02 tủ tài liệu bách khoa of acute poisoning, and. where the effects are markedly different, from oral exposure rather than inhalation. Other handbooks cover acute poisoning.16593 02 tủ tài liệu bách khoa
If such poisoning has occurred, one should consult local poison control authorities.WATERBORNE DISEASE OUTBREAKSDrinking water quality has improved drCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoaent, protection, and treatment of water supplies. However, these improvements are being threatened by the pressures of an increasing population and an aging infrastructure.Despite many improvements, waterborne disease continues to occur at high levels. Between 1980 and 1996, 402 outbreaks were repor 16593 02 tủ tài liệu bách khoated nationally with over 500,000 associated cases of waterborne disease (Figure 2.1, Table 2.1). However, the 111 *1 i r i r Ỉ itznfarkArna JirDara en16593 02 tủ tài liệu bách khoa
rar 111*1 fl 11 K f d fl 1 5ora nnf I’d r t d fl T-*diiz rfnfarHEALTH AND AESTHETIC ASPECTS OF WATER QUALITY2.3recognized in a community or, if recognCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoaredominantly diarrhea) do not seek medical attention. For those who do, physicians generally cannot attribute gastrointestinal illness to any specific origin such as a drinking water source. An unknown, but probably significant, portion of the waterborne disease is endemic (i.e., not associated with 16593 02 tủ tài liệu bách khoa an outbreak) and thus is even more difficult to recognize. Based on this information, the number of waterborne disease outbreaks and cases is probabl16593 02 tủ tài liệu bách khoa
y much greater than that recorded or reported.Yet, this difference between what is occurring and what is being reported may be decreasing. There appeaCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoar, newly recognized agents of waterborne disease are being identified and sought in the water. Improvements in sampling and analytical techniques have also improved the recognition of waterborne disease.A number of microorganisms have been implicated in waterborne disease, including protozoa, viruse 16593 02 tủ tài liệu bách khoas, and bacteria (Table 2.2). Waterborne disease is usually acute (i.c., rapid onset and generally lasting a short time in healthy people) and most oft16593 02 tủ tài liệu bách khoa
en is characterized by gastrointestinal symptoms (e.g., diarrhea, fatigue, abdominal cramps). The lime between exposure to a pathogen and the onset ofCHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoaryptosporidium ).The severity and duration of illness is greater in those with weakened immune systems. I hose organisms may also produce the same gastrointestinal symptoms via transmission routes other than water (e.g.,food and direct focal-oral contact), rhe causative agent is not identified in ab 16593 02 tủ tài liệu bách khoaout half of the waterborne disease outbreaks.Most outbreaks are caused by the use of contaminated, untreated waler, or arc due to inadequacies in trea16593 02 tủ tài liệu bách khoa
tment: the majority tend to occur in small systems (Craun. 1986).Year2.4CHAPTER TWO2.1 Waterborne Disease Outbreaks in the United States. 1980 to 1996CHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program Man 16593 02 tủ tài liệu bách khoa Norwalk virus159437CHAPTER 21Research ScientistConsumer and Environmental Health Services New Jersey Department of Health and Senior Services Trenton, NJ! ...Program ManGọi ngay
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